I've spent some more time working on Notes functionality. Each 'card' now has an icon to view it in isolation rather than as part of a list – this also serves as a permalink for each note.
Rather than treat archiving as applying a label there is now a toggle. This toggle applies the 'Archive' label in the background by checking/unchecking a hidden checkbox and updating the note as though I was doing it manually.
I'm mulling over how I can increase utility to better facilitate cross-linking between notes making it more like the Garden in that respect but don't know, yet, how that could be best achieved.
Overall, I'm pretty happy with how Notes is shaping up.